Organic agricultural market. Declining markets and prices for conventionally grown products, coupled with concerns of ecological, environmental, and health, are factors motivating growers to pursue ‘organic’ markets, which are growing at a rate of over 20% per year. There are, however, problems and challenges inherent to organic farming systems where conventional use of synthetic pesticides, herbicides and fertilizers is not tolerated. For example, while weeds may be controlled by tillage, tillage is not only labor intensive, but also exposes the soil to wind and water erosion thus depleting organic matter. Moreover, the acreages of organic crops have been limited by the cost of mechanical weed control methods.
Accordingly, the use of natural products as herbicides has the potential to significantly leverage financial resources by reducing tillage operations and labor requirements, so that acreages of organic crops can be increased.
Glucosinolates, and Glucosinolate-Containing Plant Materials.
Many plant species are known to have allelopathic effects (negative and positive) on other plant species, and this property can be exploited for weed control purposes. Over 500 plant species contain glucosinolates, of which 16 glucosinolate families are known. While there is a large variety of glucosinolates, there is a common common glycosinolate substrate core structure (e.g., glucose residue linked by a thioglucoside bond to an amino acid derivative) (formula 1), wherein the “R” group is varied between and among different plants.

Based on this core structure, the release of the alleopathic compounds from glucosinolates is primarily mediated by a β-thioglucosidases enzyme called myrosinase, explaining, at least in part, the herbicidal (allelopathic; germination inhibitory) effects of many glucosinolate-containing plants (e.g., meadowfoam (Limnanthes alba) and plant seed materials
Meadowfoam.
Meadowfoam (Limnanthes alba) is an exemplary glucosinolate-containing plant material. Meadowfoam is a herbaceous winter-spring annual grown as a commercial oilseed crop primarily for its seed oil comprising unique C20 and C22 fatty acids (e.g., for the lubricants, plastics, cosmetic and pharmaceutical industries). Meadowfoam seedmeal (MSM) is a spent seed byproduct of the solvent extraction process used to remove meadowfoam oil from meadowfoam seed. Meadowfoam seeds are also a rich source of glucolimnanthin (GLN), a glucosinolate that releases a toxic isothiocyanate upon crushing of the seeds. This release of toxic compounds, mediated by a thioglucosidase enzyme called myrosinase, explains, at least in part, the known herbicidal (allelopathic; germination inhibitory) effects of Meadowfoam seeds. The industrial-scale oil heat-extraction process destroys any enzyme activity in the seeds. Thus, while the spent seed material, meadowfoam seedmeal (MSM), contains 2-4% glucosinolate, the MSM has relatively little allelopathic (germination inhibitory) activity absent its conversion to alleopathic compounds. MSM, therefore, aside from its potential use as an exogenous plant growth substance (see, e.g., U.S. Pat. No. 6,596,323), has been generally regarded as a problematic waste product of the seed oil extraction process—at least until the present invention.
There is therefore, a pronounced need in the art for novel, cost effective natural herbicides that can be used in the context of organic farming and gardening. There is a pronounced need in the art for novel, cost effective natural herbicides based on processed glucosinolate-containing plant material, such as the exemplary MSM.
Other Markets and Utilities for Glucosinolate Breakdown Products.
As discussed herein below, in addition to herbicidal utility, glucosinolate-derived compounds have been used as fungicides, insecticides, bacteriostatic or bactericidal agents, cosmetic additives, and cosmeceutical and/or pharmaceutical agents (e.g., cancer, chemoprotectant, anti-aging, bacteriostatic, bactericidal, treatment and/or prevention of ulcers, treatment and/or prevention of gastritis, treatment of skin disorders including but not limited to eczema, facial eczema, dermatitis, external ulcers, welts, rashes, insect bites, allergic reactions and other irritations, burns, wounds, psoriasis, acneiform eruptions, dryness, dry skin, irritation, skin atrophy, secondary infections and the like).
There is therefore, a pronounced need in the art for novel, cost effective natural fungicides, insecticides, bacteriostatic or bactericidal agents, cosmetic additives, and cosmeceutical and/or pharmaceutical agents.
There is a pronounced need in the art for novel, cost effective methods to provide such products from processed glucosinolate-containing plant materials, such as the exemplary MSM.